I recently installed 3 CT101 Thermostats (multi-zoned system). I had no c-wire easily available, so am going just battery operated for now.

I am using the stock handler for the CT100, which is giving me humidity and battery reporting (in addition to temperature, setpoints, etc).

My question is that the battery reporting keeps fluctuating. For instance, last night my downstairs one said it was at 95%, but this morning it reports 100%. Just wondering if anybody else is having this “issue”. Obviously I’d love it if the 100% is correct, but I care more about a correct reading.

battery voltages do twitch up and down as they age. It’s up to the device firmware to filter it out, or not. Every device can use its own curve to decide the percentage too, so you cannot necessarily compare one device reported % / voltage to a different device.

I use rechargeables where I can, so I am used to seeing low starting voltages/% . I don’t care about 100% or 95%,but hopefully my 10% is close to an Alkaline battery 10% , because you’d expect the device to stop working somewhere less than 10%. Weekly checking for activity or battery, is how I keep my devices operating. Smart-app “Simple Device Viewer” makes this fairly low-effort to monitor reported-battery% and last-known-activity.